Improved burglar-alarm



'H. B. ROBBINS.

Burglar Alarm. I

Patented June 18, 186.7,

fnvenir i Mi'neaaea M M i N. PETERS, mmumo n m Washinglon. ac.

UNITED STATES PATENT ()FFIGE;

HENRY It. ROBBINS, OF BALTIMORE, MARYLAND.

IMPROVED BURGLAR-ALARM.

Specification forming part of Letters Patent No. 65,949, dated June 18, 1867.

To all whom it may concern Be it known that I, HENRY R. ROBBINS, of Baltimore, in the county of Baltimore, State of Maryland, have invented a new and useful Improved Burglar-Alarm; and I do hereby declare the following to be a full, clear, and exact description of the nature, construction, and operation of the same, sufficient to enable one skilled in the art to which it appertains to construct and'use the same, reference being had to the accompanying drawings, which are made part of this specification, and in which the same letters indicate similar parts.

Figure l is a perspective view of the device ready to attach to the door. Fig. 2 is a longitudinal section. Fig. 3 is aview of a holder intended to afford the means of fastening by hooks, instead of driving the spurs into the wood of the door-jamb. Fig. 4 is a transverse or horizontal section on the line a. b, Fig. 1.

Two spring piston-hammers are so arranged as to be released by the opening door, which touches the trigger and causes them to explode the caps. The nipple has a projecting point and the hammer a corresponding depression to secure explosion. The instrument is attached to the door-jamb by penetratingpoints or by hooks.

In the drawings, A is the frame of the instrument, made of metal, and having two barrels bored out, each of which contains a pistonhammer, B, and a spring, whereby the hammer is projected violently upon the cap on the nipple 0 when released by the motion of the trigger D and catch E. The latter is hinged to the frame, and has two projections, which reach into the respective barrels, and act as detents to the hammer when retracted, by catching in notches b in the hammers.

F F are pointed. spurs in the frame, by

which it is secured into the door-jamb M, as shown in Fig. 4, so that the trigger D may extend across the path of the opening door N, as shown, and be moved by the opening door, as shown, so as to vibrate the trigger D on its axis and draw back the catch E, so that its projections aredrawn from the notches b in the hammers, and the latter released to explode the caps. The trigger-plate d is made. to fold back upon the frame for convenience of carriage when required; but when in the act of releasing the lever E and the hammer, the heel end of the plate d-comes in contact with the lug on the trigger and causes it to vibrate, as stated. A spring, g, presses upon the lever E and holds it down, except when raised by the trigger. Fig. 3 shows a holder, G, whereby the instrument ,may be attached without driving the pointed spurs into the door-jamb. The holder G is fastened to the door by means of a screw passing through its central opening, and the hooks shown in Fig. 2 are hooked into the openings h of the holder G. One or both of the pistonhammers can be retracted at once.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is

The combination of the frame A, spring piston-hammers B B, lever-catch E, hinged trigger D d, and spring 9, constructed and operating substantially as described and rep resented.

To the above specification of my improvement I have signed my hand this 26th day of February, 1867.

HENRY R. ROBBINS. Witnesses: NATHAN K. ELLSWORTH, ApM. TANNER. 

